Comparative aspects of dietary copper and zinc deficiencies in pregnant rats

The utilization and distribution of copper during dietary copper deficiency was studied in the pregnant rat, and the effects of maternal copper deficiency on fetal development were compared with those of maternal zinc deficiency. Sprague-Dawley rats were fed from mating to term (per gram diet): 1) a control diet (10 micrograms copper, 100 micrograms zinc) or 2) a copper-deficient diet (0.7 micrograms copper, 100 micrograms zinc) or 3) a zinc-deficient diet (10 micrograms copper; 0.7 micrograms zinc). Dams fed the copper-deficient diet deposited only 15.5% of the dietary copper consumed during pregnancy into the products of conception (fetuses, uterus and placentas); in comparison dams fed the zinc-deficient diet deposited more zinc into their litters than was consumed (240%). Copper concentration in the fetuses of copper-deficient dams was 30% of that of controls, but the size and number of live fetuses was unaffected. The zinc concentration of the zinc-deficient fetuses was 78% of that of the controls, and both the size and number of live fetuses were considerably lower than normal. Accumulation of copper in the products of conception may be accounted for by dietary copper intake, whereas accumulation of zinc in fetuses of zinc-deficient females is dependent in part on catabolism of maternal tissues.